1. Field of the Invention
This invention relates to a process control method, a data registration program, and a method for manufacturing an electronic device, and more particularly to a process control method for a surface mount line for manufacturing an electronic device by packaging components on a substrate, a data registration program used in this process control method, and a method for manufacturing an electronic device using this process control method.
2. Background Art
An electronic device is manufactured by packaging components on a substrate using a surface mount line provided with a solder printer, a mounter, and a reflow furnace. On the surface mount line, components are soldered to the substrate by printing solder on the substrate, mounting the components on the substrate, and then melting and solidifying the solder. Conventionally, in such a surface mount line, the quality of the electronic device is controlled by controlling the process condition of each apparatus constituting the line (see, e.g., JP-A 2004-249673 (Kokai)).
The method of controlling the quality of a product by controlling the process condition of each apparatus is successfully applied to the case where the process condition has high controllability and the quality of the product depends almost only on the process condition such as in the manufacturing line for semiconductor devices. However, this method is not successfully applied to the surface mount line. This is because, in the surface mount line, the quality of the product (electronic device) greatly depends on the state of materials such as the quality of the substrate and the viscosity of solder paste in addition to the process condition, and the process condition is not in one-to-one correspondence with the quality of the product. For example, the viscosity of solder paste varies with time after opening the container and with ambient temperature and humidity. The mounting position accuracy also depends on the type of components. Furthermore, the quality of the product may be deteriorated by the inherent defect of the substrate. Hence, in the surface mount line, accurate process control cannot be achieved by simply controlling the process condition.